The Scottish elections have been marred by a huge number of spoiled ballot papers, apparently caused by the complicated system being used. As well as the first past the post and regional lists for the Scottish Parliament, the council ballot, for the first time, featured the Single Transferable Vote System. Here is a guide to how they were supposed to work.

BALLOT PAPER ONE - X MARKS THE SPOT

SCOTTISH PARLIAMENT

The Scottish Parliament is made up of 129 MSPs.

73 are elected to single-member constituencies and 56 to one of eight multi-member regions

Voters will cast two votes to elect MSPs to their constituency and region using the Additional Member System (AMS) on a single ballot paper

AMS is a combined electoral system consisting of first-past-the-post and an element of proportional representation

1.Voters use the first ballot paper to elect members of the Scottish Parliament

2. The left side of the ballot paper is peach, the right side is lilac

3. You get two votes on this ballot paper

4. The peach side is where you choose your regional MSPs

5. The lilac side is where you choose your constituency MSP

6. You put an X on each side to indicate your choice

7. Do not fold the ballot paper when you put it into the appropriate box

BALLOT PAPER TWO - NUMBERS NOT X'S

SCOTTISH COUNCILS

There are 32 councils which have 1,222 elected councillors

On 3 May, for the first time councillors will be elected using the Single Transferable Voting system (STV). This is a form of proportional representation

Each council is divided into multi-member wards containing either three or four councillors. Voters rank their choices, 1, 2, 3, 4, and so on, where 1 is the most preferred

They can vote for as few or as many candidates as they like

1. Voters use the second ballot to elect their local councillor

2. This is the white ballot paper

3. You do not use a cross for this vote

4. You number the candidates in order of preference

5. Your first choice is marked 1, your second choice is marked 2, your third
choice is marked 3, and so on

6. You can mark as many or as few as you like, but you must use numbers not an x

7. Do not fold the ballot paper when you put it into the appropriate box

WHAT WENT WRONG?

REJECTED PAPERS

Airdrie and Shotts 1,536

Cumbernauld and Kilsyth 803

Dumfries 1,006

Dundee East 913

Dundee West 978

Glasgow Anniesland 1,736

Glasgow Baillieston 1,850

Glasgow Kelvin 1,195

Inverness East 1,249

Motherwell and Wishaw 970

Shettleston 2,035

Polls have been hit by major problems with some counts suspended and an unprecedented number of spoilt ballots papers recorded.

As many as 100,000 votes may have been discounted across Scotland because they were classed as spoilt papers.

Concerns have been raised about the decision to stage the Scottish Parliament and the local authority elections on the same day.

Voters were presented with two ballot papers and two different voting systems, which may have caused confusion and led to spoilt papers.

In many areas, there were problems with electronic counting machinery being used for the first time.

In a statement, the Electoral Commission said it would be "undertaking a full, independent review of the elections in Scotland. In particular, it will be focusing on the reasons for the high number of rejected ballots; the electronic counting process; and the arrangements for postal voting."